Sat, 28 Jun 2025 06:22:46 UTC
this one would like to get tattoos someday. however, they cost money. additionally, it feels like it wants to test run them before committing to something permanent. introducing: custom temporary tattoos. at some point the idea to get a qr code tattoo turned into thinking about ways to test run such a tattoo. the solution it came up with is, to its knowledge, not particularly widespread.
the general strategy is to 3d print a stamp, cover it in sharpie, then lightly apply isopropanol to the skin and press the stamp on. the isopropanol helps to transfer the sharpie from the stamp to the skin. it is likely that half of the ink stays on the stamp but in this ones experience this tends not to be a problem. it is possible to touch up the tattoo using an ultra fine point sharpie after it is stamped. in the event that the tattoo is unrecoverable, one may wipe it away using more isopropanol and try again.
depending on the geometry of the location the stamp is being applied to, it may not be possible to use a flat stamp. one may heat up the stamp using the 3d printers heated bed as a hot plate, making it somewhat pliable, then bend it into a curved shape. this will likely have the effect of compressing the image in one axis, so one may wish to scale the model in that direction accordingly before printing. it is worth noting that for qr codes this will likely not affect functionality due to the skew correction qr code scanners apply.
qr code skew correction assumes the code is on a flat plane. it cannot compensate for image distortion caused by the code being on a curved surface. generally this can be worked around by ensuring that the scanning device is directly perpendicular to the center of the code. this limitation is not present with 1d barcodes but this one has not experimented with those yet.
a word of caution: not all markers are skin safe. standard sharpies are generally skin safe as long as they are not applied to open cuts. nonstandard sharpies, such as metallic sharpies, should be assumed to not be skin safe unless proven otherwise. "king size" and "magnum" sharpies are not skin safe as they are formulated with xylene. do not apply xylene to the skin.
this one has found that version 1 qr codes (21x21) work well when printed at 48x48mm. it is important to apply the stamp while any applicable joints are in the orientation they are expected to be in during scanning. this helps prevent skew.
if one has any questions about this process, or would like to show off what it has done using it, they are encouraged to contact this one; it would love to see! contact information is available on the homepage of this site.